Enthylene on combustion gives carbon diocxide and water. Its enthalpy of combustion is 1410.0kJ // mol.If the enthalpy of formation of CO_(2) and H_(2)O are 393.3kJ and 286.2 kJrespectively, calculate the enthalpy of formation of ethylene.

Enthylene on combustion gives carbon diocxide and water. Its enthalpy

1.	Enthylene on combustion gives carbon diocxide and water. Its enthalpy of combustion is 1410.0kJ // mol.If the enthalpy of formation of CO_(2) and H_(2)O are 393.3kJ and 286.2 kJrespectively, calculate the enthalpy of formation of ethylene.
Answer» Solution :Given `:` (i) `C_(2)H_(4)(g) +(5)/(2) O_(2)(g) RARR 2CO_(2)(g) + 2H_(2)O(l), DeltaH = - 1410.0 kJ mol^(-1)` (ii) `C(s) + O_(2)(g) rarr CO_(2)(g), DeltaH= - 393.3kJ mol^(-1)` (iii) `H_(2)(g) + (1)/(2) O_(2)(g) rarr H_(2)O(l), DeltaH = - 286.2kJ mol^(-1)` Aim `: 2 C(s) + 2H_(2)(g) rarr C_(2)H_(4)(g) DeltaH = ?` ` 2 xx ` Eqn. (ii) `+ 2 xx `Eqn.(iii) - Eqn. (i) gives the REQUIRED result.